Skill Shop

It would be good, but I'm very doubtful. Having the skills locked like this gives people reason to summon, which means they need to buy orbs, which means IS makes money.

I feel like, if they're gonna do this, they would do it with 5-Star Combat Manuals of characters with those skills and have them on a rotation (so one season (I dunno how long these would be), you'd be able to get Owain/Hardin/Lewyn/Takumi, the next could be Karla/Ishtar/Hector/Genny, and so on), while also having the 3/4-Star pool always available (and cheaper than the 5-Star-exclusive Manuals, though they'd be bought as 4-Star Manuals) so you could get infinite Fury/Desperation/ATK Smoke/whatever fodder all the time. And they would all use Heroic Grails, because Arena Medals stay useless... but maybe you'd be able to turn spare Arena Medals into Heroic Grails at an exchange rate of, say, 20 Medals = 1 Grail.

This is just what I'd expect. I do prefer your idea though!

I feel like this is coming in the 3.0 update, but I feel like there will be a currency like grails introduced, and you'd be summoning 4* copies of units. Meaning it would be Hinata, Beruka, etc to get skills. I don't forsee any super powerful units like Hector/Takumi, Brave Ephraim, etc appearing in this area. I feel like it would be launch units at best, with units up through the first few months of the game which are not seasonals, and wouldn't even include the first brave units. This changes things to have the rare skills available at a pinch, or even free merges. But it is not a game changer to give everyone access to Fury, QR2 and others. I've even uncertain with units like Selena/Barst who carry reposition seeing as that's easily one of the best assists in the game (by functionality, obviously not points/SP)